Research on One Optimization Relay Protection Scheme of Offshore Wind Farm

Abstract

[Introduction] To improve the utilization efficiency and save the investment cost, the relay protection area and operation time in offshore wind farm need to be optimized. [Method] This paper eliminated the circuit breaker of 220 kV submarine cable outlet side, and steed the three-phase split current differential full range of rapid "T" zone protection for 220 kV submarine cable small bus. At the same time, the 35 kV station and 35 kV grounding transformer were combined, using simple 35 kV bus protection, and increasing the low pressure side of the main transformer zero sequence CT. [Result] The result shows that the optimization relay protection scheme can save a 220 kV circuit breaker and two sets of 220 kV bus differential protection investment. At the same time, the 70 m2 of space and corresponding investment cost of offshore substation can be saved. And the sensitivity and reliability of the protection configuration has been improved. [Conclusion] Finally, the optimal scheme of offshore wind farm relay protection is economical and reasonable, and it is expected to be applied in engineering practice.

Keywords

• offshore wind farm
• relay protection
• t zone protection
• simple bus protection